I've been watching a lot of videos of the RBs since we need one, and of those 5 listed, only Lloyd interests me. Estime and Irving are on the smaller side and get by on juking people, but they aren't really fast. I think they'll get swallowed up in the NFL. Benson is a little bigger but plays like them. Brooks has the kind of injury that makes him a huge question mark. He might've been the first back to go. But unless a team makes a run at him like the Bills with Willis McGahee, he might even be there in the 4th.
I like Lloyd as a 3rd down back. Pass catcher.
I'd be interested in the 5th round in Braelon Allen, a big bruising back who can't seem to make people miss but can get you 3 yards at any time. I like Will Shipley as a 4th rounder; kind of a Kevin Harris story but with a lot more athleticism. With Shipley, you can hit big even though he had a down year opposed to previous years (like Harris). Late round interests in 6th or 7th: Dillon Johnson (because he's a tough SOB), Emani Bailey, Corey Schrader. All 3 are going to make the NFL as capable backups.
My favorite back: Blake Corum. I see him as having the potential to be a good home run hitter. A James Cook type. I would spend a 3rd on him. It's likelier that, given the team's needs, they'll only spend a 5th thru 7th, which makes Rham the lead back and keeps Kevin Harris as his backup.
So you're back really to targeting Lloyd in the 4th or 5th as your 3rd down back.